FIG. 1 shows a schematic cross-section of a conventional drum type washing and drying machine (see JP 2001-149689 A, for example).
The drum type washing and drying machine includes an outer casing 1, a water tank 4 placed in the outer casing 1, a rotary drum 5 placed in the water tank 4 and intended for accommodating a wash, a transparent inflexible outside door 3, an automatic door opening/shutting mechanism 10, and a dryer unit 24 for drying the wash.
On a front face of the outer casing 1 is formed an outer casing opening 1a. A wash is put in and taken out through the outer casing opening 1a. The outer casing opening 1a is opened and shut by the outside door 3 that is slidable upward and downward with respect to the outer casing 1. On upper part of the front face of the outer casing 1 is provided an operation panel 11 having operation keys, display units, and the like. A control unit 2 for controlling operation of the drum type washing and drying machine is provided on reverse side of the operation panel 11 (on a side of the water tank 4), and thus input into the operation panel 11 allows successive or separate performance of a washing process, a rinsing process, a dewatering process, and a drying process. The outer casing 1 elastically supports the water tank 4 through medium of a suspension 8 as an example of an elastic support unit.
The water tank 4 has a shape of a bottomed cylinder with a water tank opening 4a that opens in face of the outer casing opening 1a, and is positioned transversely and slantly so that rear side thereof (bottom side of the water tank 4) is in lower position. The water tank opening 4a and the outer casing opening 1a face each other with a space between. A transparent lid body 6 is mounted on the water tank with use of hinge mechanism, so that the water tank opening 4a can be opened and shut by the lid body. On the lid body 6 is formed convex part 6a that protrudes toward inside of the rotary drum 5 when the opening 4a of the water tank 4 is shut. A sealing member 41 is provided on inner circumferential surface part of the water tank opening 4a and, while the water tank opening 4a is shut by the lid body 6, the water tank opening 4a is held watertight by intimate contact between the sealing member 41 and the convex part 6a. 
The rotary drum 5 has a shape of a bottomed cylinder with a drum opening 5c that opens in face of the water tank opening 4a, and is positioned transversely and slantly so that rear side thereof (bottom side of the rotary drum 5) is in lower position. A motor 9 is connected to backside of the rotary drum 5 through a shaft 5e, and drives the rotary drum 5 to rotate in accordance with control by the control unit 2. A plurality of small bores 5a are formed on a whole area of a circumferential wall of the rotary drum 5. The small bores 5a allow circulation of washing water (water such as tap water and bath water or water containing detergent or the like), dry air or the like between a space between the water tank 4 and the rotary drum 5 and a space in the rotary drum 5. On an inner wall surface of the rotary drum 5 are provided baffles 5b protruding inward in radial directions. The baffles 5b are provided circumferentially at three sites at intervals of 120°, for example, and repeatedly lift up and drop the wash with rotation of the rotary drum 5. When the rotary drum 5 is rotating, a fluid balancer 5d that surrounds the drum opening 5c from outside reduces unbalance caused by one-sided wash and washing water, through agency of motions of fluid sealed in the fluid balancer 5d. 
The dryer unit 24, which has a blower 31 and a heater unit 32, is provided on top of the water tank 4. In the dryer unit 24, the blower 31 is positioned on rear side and the heater unit 32 is positioned on front side with respect to front and rear of the drum type washing and drying machine. The blower 31 includes blower blades 34 in a casing 33 and a fan motor 35 for driving the blower blades 34 to rotate, which motor is provided outside the casing 33. The fan motor 35 is directly connected to the blower blades 34 so as to drive the blower blades 34 to rotate with use of a direct drive structure. On the other hand, the heater unit 32 includes a heater 36 in a heater case 26, and inlet part of the heater case 26 communicates with outlet part of the casing 33 of the blower 31.
At bottom of the water tank 4 is provided a drain valve 20 that is opened/shut by a drain valve motor not shown. Upon opening of the drain valve 20, water in the water tank 4 is drained through a flexible drain hose 19 to outside.
In the outer casing 1, a blower duct 38 is placed on front side of the water tank 4. One end of the blower duct 38 communicates with outlet part of the heater case 26, and the other end of the blower duct 38 forms a jet 38a communicating with inside of the water tank 4 and inside of the drum opening 5c in peripheral part of the water tank opening 4a. That is, the blower duct 38 and the jet 38a act as a blower unit for supplying heated air toward inside of the rotary drum 5 through the water tank opening 5c. 
In addition, a dehumidifier 27 is provided on back side of the water tank 4 in the outer casing 1. With water poured into the dehumidifier 27 through upper part thereof, the dehumidifier 27 performs dehumidification by cooling and condensing water content in air that passes therethrough. The dehumidifier 27, which is hollow as a whole, has a water inlet 27a and an air outlet 27b in the upper part and has an air inlet 27c doubling as a water outlet in lower part thereof. The air outlet 27b of the dehumidifier 27 communicates with inlet part of the casing 33 of the blower 31, and the air inlet 27c communicates with lower part of inside of the water tank 4. To the water inlet 27a is connected a feed water supply system not shown.
In accordance with the drum type washing and drying machine having the above configuration, a user opens the lid body 6 directly and manually, thereafter puts a wash into the rotary drum 5 through the outer casing opening 1a, and then shuts the lid body 6 directly and manually. Thus inner rim 41a of the sealing member 41 is brought into intimate contact with rim of the lid body 6 so that the water tank 4 is sealed. When the user manipulates the operation panel 11 so that a washing operation is started on basis of an instruction from the control unit 2, the automatic door opening/shutting mechanism 10 initially slides the outside door 3 in an upward direction in the drawing along a front panel 7. Then the outside door 3 shuts the outer casing opening 1a, as shown in FIG. 2, while making a track generally shaped like an arc. Upon termination of the washing operation, subsequently, the automatic door opening/shutting mechanism 10 slides the outside door 3 in a downward direction in the drawing along the front panel 7. Thus the outer casing opening 1a is opened again as shown in FIG. 1. After that, the user opens the lid body 6 directly and manually and subsequently takes the wash out of the rotary drum 5.
In a drying operation, the blower 31 is driven to rotate while the heater 36 is energized for heating. Thus air supplied by the blower 31 is heated by the heater 36 while passing through the heater case 26, and the air having got a high temperature is forwarded through the blower duct 38, the jet 38a, and the water tank opening 5c toward the wash in the rotary drum 5, so as to dry the wash. The hot humid air having absorbed moisture of the wash in the rotary drum 5 is exhaled, from the small bores 5a formed on a circumferential surface of the rotary drum 5, into the space between the rotary drum 5 and the water tank 4. The space between the rotary drum 5 and the water tank 4 communicates with a space around the dehumidifier 27, as described above, and the air flowing around the dehumidifier 27 comes into contact with a wall of the dehumidifier 27 cooled by cold water flowing through the dehumidifier 27, then forms dew, and thereby undergoes dehumidification. The dehumidified air is forwarded afresh by the blower 31 via the heater 36 into the rotary drum 5. In this manner, the process of drying the wash in the rotary drum 5 is carried out. Such a drum type washing and drying machine is disclosed in JP 2001-149689 A, for example.
In the drying process in the drum type washing and drying machine, however, the action of lifting up a wash by the baffles 5b and thereafter dropping the wash is repeated with the rotary drum 5 rotated at a low speed and, in progress of the drying process, minute dust such as lint, fluff, or fuzz appears from the dried wash. Such minute dust may enter into the casing 33 with the air circulation caused by the dryer unit 24.
In the washing process or the rinsing process, normally, such foreign matter as lint in washing water is removed by a filter unit or the like (not shown) provided before the drain valve 20; in the drying process, however, such foreign matter circulating with air passing through the dryer unit 24 is not removed and may adhere to a shaft linking the blower blades 34 to the fan motor 35 and may form a resistance against the rotation of the blower blades 34 and the shaft, which resistance may degrade blowing capacity of the blower 31 with long-term use thereof.